Direct-current transformer



mme@ Ma. 15, 1921.

5 SHEETS-sum1."

FIGA. l

I E C' f 2 V f 2 @I :I

55; 2 E. v/-/. E E

f/m L /UQLIJLLJ ("b 3 i "I @gg y I IPJITNESSES A. F. NESBIT.

DIRECT CURRE'NT TRANSFORMER..

APPLlcATloN FILED APR. 25, 19.17.

15mm@ f mm@ Maf., @L

5 SHEETS-SHEET 2.

WITNESSES DIRECT CURHEN? TRANSFORWER.

5 SHEETS-81112514.

A. F. NESBH.

nmsc CURRENT RANsFomnER.

APPLICATIH HLED APR. 25, 1917. A J I 'd @named Mal. @5, WZL

'5 SHEETS-SHEE15.

INUENTOR .4;

c :if fili; n diff. J;

Parana orifice.

ARTHUR F. NESBIT. 0F VLKINSBURG. PENNSYLVANIA.

:DIRECT-CURRENT TRANSFORMER.

Application led April 25,

To all whom t may conce/"n Be it known that l, ARTHUR F. NnsBiT, acitizen of the United States, and resident -of llvilkinsburg, in' thecounty of Allegheny and State of Pennsylvania, have invented' -certainnew and useful rImprovements in determined value, from an alternating.

curient. l

Another object of this invention is thev production of a direct currenttransformer wherein a stationary stator and a stationary or locked rotorare employed, and whereby a unidirectional current of high potential isobtained from an alternatingcurient of any voltage, frequency oi' phasecombina tion.

Another object of my invention is to prvide a transformer wheiein theprimary or stator and secondary or rotor core's are integrated andwhereby a direct current of any desired voltage is obtainable.

A further object of the invention isto provide a high voltage, directcurrent transformer having improved means whereby sparkless commutationiseffected, this result being accomplished by means of a commutatingfield which is angularly adjustable about the axis of a primary core anda secondary core.

A further object of the invention is to provide a high potential directcurrent transformer wherein the mass and number of the moving parts ofthe apparatus areA reduced. i'

A still further object of my invention is to provide a transformerhaving the parts and novel constructions, arrangements, andcoinbinations of parts illustratedin the drawings` to be described indetail hereinafter, and to be particularly pointed out in theI appendedclaims.

As is well known to those skilled in the art, in starting inductionmotors with the rotor at a standstill, theA rotor acts as a locked rotorat the instant the circuit is .Specication of Letters Patent.

Patented Mar. 15, 1921. i917. serial No. 164,430.

closed on the stator windings, and that the rotating magnetic flux setup by the polyphase .currents energizing the stator coils gives rise toa magnetic field which cuts the rotor coils with the same frequency,that is I to say with the frequency of the E. M. F.

impressed upon the stator coils.

In constructing transformers in accordance with my invention a rotor isprovided which is fixed or permanently located with reference to thestator. And to that end the laininae of the coies preferably will beinte-- grally formed and will be provided with a series of rectangularor approximately rec-` tangular openings, the openings in the laminzeforming the built up cores registering to form a series of-slots or gapsthrough which 'the windings of the'stator and rotor coils extend.

Referring now' to the drawings, forming part of this specification,Figure l is an' elevation, partly in section and partly diagrammatic,showing a high potential, direct citrient, vertical transformer, e. atransformer having an axially vertical commutator shaft), constructedand arranged in accordance with my invention.

Fig. 2 is adiagrainmatic plan, on a somewhat larger scale (with thecoinmutating field core and its windings omitted for the sake ofcleainess), showing a preferred grouping of the series of high voltagecoils lon the locked rotor, and showing the connections between therotor coils and the conimutator, y on the commutator shaft in theparticular` construction illustrated in Fig. l,

Fig. 3 is a sectional elevation of the cores v and the windings or coilsof the stator and rotor cores (shown in the preceding figures,)

and the coinmutating field cores, the section being taken on the lineIII-III of Fig. 2.

Fig. 4 is a diagrammatic plan, similar to that of-Fig. 2, show'ng thecoinmutating field cores and the win ings and connections to thewindings on the axially adjustable primary commutating field core.

Fig. 5 is a plan showing details infthe construction and arrangement ofthe slip rings and commutator segments and leads therefor as mounted onthe commutator shaft and shown diagrammatically in Fig. 2.

Fig. 6 is an elevation, partly in section and partly diagrammatic, likethat of Fig. 1, showing a horizontal transformer or transformer modifiedto have an axially horizontal commutator shaft and having a plurality ofstator and rotor cores and commutating field cores constructed andarranged in'accordance with my invention.

Fig, 7 is a detail plan showing a commutator shaft having a multiplegroupof commutators, slip rings and bus bars 'arranged -thereon inaccordance with my invention as constructed for use with theapparatus ofFie. 6.'

i' n the accompanying drawings the letter vA designates the primary orstator'core and B the secondary or locked rotor core7 of the annular,integrated'structurev forming these cores. By integrated, as usedherein, is

meant -a laminated rstructure [having each lamina transversely dividedinto a series of segmentsv and each segment forming part of the core Aand also part of the core B. When yconstructed as shown, the cores havewindings thereon forming twelve primary or stator coils al, a2, a3, af,a5, a6, a7, as, a9,-

@10,a, and (L12, and equal number of secondary orlcked rotor coils b1,b2, b3, b4, b5, b, 67, bs, 69,2110, b, and Z112.

Mounted aboveand in axial alinement with the stator andi-rotor cores arethe commu-'gv tating ield cores C and C1 of my improved transformer. Theangularlyadjustable pri-I mary field core C has windings thereon 01, c,and 0,12. 'The lstationary secondary commutating field core .C1 isembraced orA encircled by the windings forming the coils ,61, b2, 3,etc., of the locked rotor B (as is shown in Figs. 1, 2 and 3.)

Extending vertically through the axiallyY central and. axially alinedopenings in the cores B and C is a rotary commutator shaft.-

D and positioned on this shaft adjacent to its upper end, is a segmentalcommutating group or commutator E (Figs;'2 and 5) and coperating groupof )slip rings E, to which the segments ofthe 'commutatorE arepermanently connected electrically. The lower end of the shaftisconnectedto the armature shaft of a synchronous motor G by which theshaft D is rotated. yThis motor, as shown, is positioned below'the oiltank or container Hin which"the .stator A, lockedY rotor B, andcommutating field Icores C'and Clare positioned so as to be submerged inthe oil. "It will beobvious ',.however, that the motor G maybesupportedV above the 'tank H ,andj be connected to the oppositefilledWithvoil toabout the level indicated byV the broken line 4, to keep thestator A 'and A tank.

H issecured on a support 2 The i rotor B immersed in the oil and providefor effective insulation of the stator and rotor, and the tank has atight cover or lid 5 on its upper end. n

' Suitable. supports G are provided above or on top of the-locked iotorcore upon which the stationary or secondary core Cl of the commutatingfield core is positioned, and similar supports T above or on top of thestationary stator core A' provide means for supporting thev angularlyadjustable, axially movablefprimary commutating field corev and seriesofwindings forming its coils c1, c2', c3, etc.

The primary commutating field core .C is arranged to turn 'angularlyrelative to the stator and rotor cores A and B and the coils al, a2,etc'.,'and 61,'112, etc., thereon, this field core C turning about thevertical axis of the stator and rotor when being adjusted relaltivethereto and a suitable manually operated adjusting mechanism-beingprovided for turning the commutating field core. C and for locking thecore C in adjusted position (see Fig.'1). j l

. As shown, the adjusting mechanism com'- pri'sesfa segmental gearorcurved rack E secured on the periphery of the core C and having teethin mesh with those of the pinion 9 on one end of .the vertical shaft 10.95' The shaft is rotatably secured in the bracket bearings 11 and12whicli are fastened to the vertical wall of the tank H, and extendsupwardly to or above the oil leyel et in the The upper end of the shaft10 is pro- V.100 vided with a. worm' wheel 13 which meshes with the worm14. on one. end of the hori-v zontal shaft 15, this shaft also beingrotatably mounted in the upper bracket bearing v12.Y The shaft 15extends through a stuffing 105, box and gland on theside wall of thetank HA and is providedfon its outer .end with a hand wheel 16 forAturning the shafts 10 and 15v to adjust the primary eommutating fieldcore C and its'coils c angularly with respect 11.0

` to the stator A and rotor B and coils a and therefor. As theadjustable commutating` field core must be held in its adjustedpositions, the worm wheel 13 and worm laconve'niently serve asa locktherefor in addi- 115v tion to transmitting motion from the shaft 15 totheshaft 10. 1

YThe rotary commutator shaft D, which is shown centeredon the verticalaxis of the annulus'formingthe cores A and B for the 120 stator androtor, (and the axis ofthe tank H), extends through a tube 17 in thetank H and is' provided, adjacent to its upper end,\

with theco'mmutator or segmental commutator groupv E and coperatinggroup F of twelve Slip rings, f1, f2', f3, a f5, a fz a a f1, f11, an'dfu The tube 17 is fastened, by a iange 18 on its lower end to the bottomof the tank'H to form an oil iight joint therebetween and aiiange19 onAitsupper end is secured to the cover or lid 5 of the tank to rigidlyfasten the tube in upright position within the tank. The vertical shaftD is rotatably mounted in bearings 20, 2l, which are secured to the endsof the tank H, and a third bearing 22, on the spider 23 is provided forthe upper end of the shaft D. The

'spider 23 is secured in position on the upper a1, 0,2, a3, etc., of thestator A and coils b1, b2, b3, etc., of the locked rotor B, when thesecoils are assembled in operative position on the cores. T o vfacilitateassembling the parts forming the integrated or unitary cores A and B,each lamina should be slitted and in building up the laminated structurethe slits in the laminas xshould be `staggered to form overlappingjoints.` Such expedient being old and well known in making laminatedcores, need not be further described.

The primary or stator circuit as shown, has a series of twelve polyphasewindings a1, a2, etc., these coils preferably being connected in Y or instar and the groups of coils having terminals m1, m2, and m2. (See Fig.2). The secondary or locked rotor circuit has a series of twelvepolyphase windings or coils b1, b2, b3, Zat, b5, b, b1, bs, b2, Z912,511, and Z 12 which are connected in closed series as in a .closed coilGramme ring-armature, the series of coils b1, b2, etc., being properlyinsulated against the potential to be carried thereby. p

Positioned immediately above the primary or stator core A and its coilsa1, a2, etc.; so as to be adjustable angularly relative to the coils onthe core A, is the primary commutating field core C and its series oftwelve windings orcoils c1, c2, c3, c1, c5, c, c7, cs, c2, 01, 011, and012. which also are connected in Y or in star, and the groups of coilshaving terminals N1, N2, N3 (Fig. 4) rand immedi- .ately above thesecondary or locked rotor core B is the secondary or stationary core C1of the commutating' field core, this core C1, being embraced orencircled by the windings forming the coils b1, b2, etc., of the lockedrotor core IB (Figs. l, 2, and 4).

The terminalsv n1, n2, and n3 of the three groups .of coils forming theprimary commutating circuit, however, are not located directly above thesimilar points m1, m2, and m3, on the main primary circuit, but aredisplaced forward or backward with reference to them. Arllhis willrepresent a maximum possible magnetic displacement of approximately 90degrees. The magnetic iiux produced by the windings c1, c2, c2, etc.,will lag or lead according to the extent of adjustment with reference tothe main primary magnetic flux.

The terminals of each coil of the electrically adjacent rot'or coils b1and b2, 62 and 3, Z13 and Zfi, b4 and b5, b5 and o, Z2 and?, Z and bs,o8 and b2, ZJ and Z212, 610 and 51,1, 511 and Z212, 512 and b1 areconnected together and have a common lead h1, ft2, h3, Zit, h5, LG, h1,its, it, IL10, h11, or k12, and these leads, as shown, are connectedeach to its individual ring 1, 2, 3,14, 5, 6, 7, 2, 2, 10, 11, and 12.The group of bus rings 1, 2, etc., which encircles the shaft D and tube17, is located Within the tank H so as to be immersed in the Oilin thistank. Each of the rings 1, 2, etc., has a' lead jl .7.2, 7.37 .7.4i.7.57 .Zas .'(71 js: .7.97 .7.101 .7.11, and .j12, which extendsupwardly through an insulated opening in the tank cover or lid 5 and isconnected by a carbon brush k1, k2, 7c3, 7a4, kilo, ZcT, las, 102, 751",7011,' and k12, to one of the slip rings f1, f2, f3, etc.,`in the groupF of slip rings fastened on and rotating with the commutator' shaft D.

Obviously the rings and leads j may be omitted, in such case the leadsZL extending to the brushes 7c for the slip rings f.

The slip rings f1, f2, etc., are permanently connected electrically byleads Z1, Z2, Z3, etc., one to each of the commutator segments c1, e2,e3, etc., forming the commutator E on the rotary commutator shaft Dadjacent to the slip rings. (See Fig. 5.)

The commutator segments e1,'e2, e3, etc., are insulated from the shaft Dand from each other in any of the various known ways and this insulationmay conveniently be utilized to support and insulate the leads Z1, Z2,etc. The necessary number of leakage rings 26 will be provided at theends of the group F of slip rings and on each side of the commutator F,and preferablya leakage ring. 26a will be supplied onthe commutatorshaft D between the adjacent slip rings f1, f2, etc., as shown in Fig.5.

By splitting up the primary windings into a-plurality of groups ofcoils, instead of vone group for each phase as shown and described inconnection with the apparatus of Figs. l, 2, and 3, a multiplicity ofrotary fields will be obtained, instead of a single two pole rotaryfield, this having the effect of decreasing the secondary voltage andincreasing the current carrying capacity of the locked rotor orsecondary circuit, by permitting the .parallel grouping of the secondarycoils.

The brush I on the commutator-E is connected to the negative leadK andthe brush directional current generated bymy improved apparatus.

The 'windings forming the primary or stator-coils al, a2, etc., areconnected in three groups of four coils each, the coils (L12, al, a2,and a3 forming one group, the coils a4, a, a, anda?, the secondl groupand the other coils as, ae, and al, .the third Vgroup. The coils of eachgroup are connected in series, the leads g1, g2, g3, fromfone terminalof the coils a3, al and all at one end ofeach gro'up being connectedinstar' and onetersource of alternating current.

Connected -in star by leads o1,'o2,'and o3.

The terminals for the synchronous motor G also are connectedl to thesourceof alternating current. j

y In the modified construction shown in Fig. 6 the grouping of the coilsvon the primary or stator cores, the secondary or locked rotor cores andthe primary commutating field cores, is the same as in Figs. .1, 2, 3,A

and 5.

VThe modified apparatus, however, has

two separate stator cores A, and' A-A, two rotor cores B and B B, twoprimary ield cores C and CC'andtwo secondaryfield cores Gland CClLyFlach rotor core has its series of cores al, a2, i12/etc., eachv statorcore its coils b1, 62,773, etc., and eachv primaryfield core itswindings or coils "el, c2,

'03, etc., and each stator and rotorl unit has its complement of sliprinV s f, 7f, et'.4 The commutator shaft being #horizontal, is mountedvat itsendsiin bearingsA 20,

21a which are secured 'on the ends fof the high pressure cover -5a forthe commutatore,

thel covervbeing supported on the coi er or'- lid jfor the tank Hf Thesynchronous rncj tor Gr for driving the oommutator shaft 'D also is`mounted on'the tank cover or lid 5, the commutator shaft' beingdirectly'connected to the armature shaft of the motor G. Each ofthejangularly adjustable, .com-

.mutating field cores Gand CC in the ap- 1 .paratus of Fig. 6.preferably is geared to.\

the vertical shaft 10 of asingle adjusting mechanism vused therewith sothat the com- 'mutat'ing field cores and coils thereon willbe adjustedin unison, inthemannershown Ain Fig. .5. The vcommutating field cores Cmay be arranged to .be 'adjusted separately and independently, however,lwhen found y necessary or desirable. -In the' apparatus of Figf twocommutators or groups of commutator segments F and F-F will be employedone foreach of the two statiom ygether so'that the plete series similarto a closed Gramme" LeT/1,994.

ary or locked rotor cores', B-B, and ,the brush J2 on one terminal ofthe commutator- F-F lwill be connected by a lead to'the terminal l ofthe opposite signl for the com` niutator F while the brush J on thelconiniutator F and brush I2 on one terminal for the ,commutator FF willlead to the apparatus ofv utilization of the generated unidirectionalcurrent. j l

' rlhe operation of my improved apparatus wi/ll now be described. Asource of alter- 'natingor multi-phase current will be connected bymeans of suitable conductors to the terminals m1, m2, 4and groups of'coils a on the stator core A, and to the terminals nl, a2, andn, forthe similarly arranged groups of' coils C on the angularly adjustablecommutating 'field core m3 for the three aoA C, and also to theterminals for the sy'nchronousmotor G.' Then current is supplied inthisv manner'the three series of primary colis a. on thestator A `areenergizedfand thereby causedv to produce a twoi coils of the secondaryor locked rotor core Bby means of the magnetic path provided'A by theintegrated cores A and B and induces electromotive forces inthe coilsb1, b2, etc., of the secondary or locked rotor core B.- The time phaserelations of the induced electromotive forces in the coils '61, i, etc.relative to one 4another will be proportionate to the relative angulardisplacement l .of these coils b1, b2, etc. Y y N These secondary orlockedrotor coilsbl, Z22, etc., are spaced or positioned in regard toone another to have an equal angular displacement andthe terminals oftheelectrically adjacent coils are connected to'- twelve coils formaicomring. l f Y At the same time the multi-phase current is supplied tothe terminals/a1, a2, and' a3.

ofthe groups of coilsfc on the primary commutating field core Cyand thecoils '01,' c2, etc., alsok are energized and are causedto produce atwo-polerotating magnetic field in thecores C and C1.` o ,Y v .The iiuXof .this rotating magnetic field also passes progressively through thesecondary or locked rotor coils b1, b2, etc.,

through thev medium ofv the magnetic path provided by the cores C andC1;

The rotary magnetic field Ain the commu# tatingfield cores C, C1,however, is not in 'space phase'relation with the primary rotatingmagnetic field induced inthe stator coils al, a2, a3, etc, but leads orlagsv behind it by approximately 90' degrees, so that in this way thedesired sparklesscommutating conditions are obtained. As the displace-Viso ment of thegroup of commutating fieldy coils c1; c2, c3, etc., isnot permanent but may be regulated and controlled angularly with respectto the coils of the stator core A by means of the adjustingl mechanismwhich -has been described, non-sparking commutating conditions equaltothose of the most modern type of standard direct current apparatus areobtained with my improved transformer. i

When found desirable or necessary secondary field coils may be added tothe core C1 which will produce a rotating magnetic field atapproximately 90 degrees magnetic displacement relative to the fieldobtained in the primary coils c on the core C so as to obtain sparklesscommutation.

The leads 71,1, 7b2, etc., which are connected at one end to the joinedterminals of the electrically adjacent coils 1 and b2, b2 'and b3, etc.,extend each to itsv individual slip ring f1, 712, f3, etc., (through itsring z'l, i2, i3, etc., when the rings are employed) and through theslip rings f1, f2, f3, etc., and permanent leads Z1, Z2, etc., to itsappropriate commutator segment el, e2, e3, etc., formin the commutatorAor commutating group l chronous motor Gr for driving the commutatorshaft is connected to a common source of alternating multi-phase currentthe commutator will be rotatedsynchronously with the current induced inthe coils of the rotor, stator and commutating field cores. The E. M.F.s,induced in the secondary or locked rotorcoils b1, b2, 5 3, etc, whenconnected in the manner described above, will be superposed one upon theother and be rectified to produce a unidirectional E M. F., the value ofwhich is dependent upon the geometrical sum of the individual E. M. F.s

induced in the secondary or locked rotor coils.

It will, of course, be understood that the synchronous motor is usedbecause it must rotate in step with the generator or transformersupplying current to it and to the coils of my improved transformer.

Modifications in the constructions and arrangements of the parts may bemade. Obviously the primary and seconda-ry cores and coils therefonmaybe interchanged to position the primary windings on the inside andsecondary windings on the outside instead of as shown, and thecommutating field cores may be similarly interchanged and als(` othercombinations may be formed so long as the same magnetic circuit isembraced by the coils, without departing from my invention as defined inthe appended claims.

l claim z-l Y l. A transformer comprising a -main field havingintegrated primary and secondary cores and a plurality of coils on saidprimary and secondary cores, a commutating on theshaft D, and as thesyn-- field having a core and a plurality of coils` ondary. cores, acommutator group connected to the coils of said secondary core, andcollectors for s aid commutator group.

2. A transformer comprising a main field having' integrated primary andsecondary cores and a plurality of coils on said primary and secondary`cores, a commutating field having a-core and a plurality of coils onsaid core, said fields being displaced approximately 90 degrees in phaseand said commutating field being angularly adjustable about the axis ofsaid primary and secondary core, a commutator` group connected to thecoils of said secondary core, collectors for said commutator group, andmeans for adjusting said commutating field angularlyrelative to saidprimary and secondary havingintegrated primary and secondary cores 'Withwindings on said primary core and on said secondary core, a commutatingfield having an adjustable core and windings on said adjustable core,said fields being displaced approximately 90 degrees in phase and saidadjustable core being axially' alined and being axially movable relativeto the main field core in adjusting the commutating field, a rotatingcommutator group and a synchronous motor for actuating the commutatorgroup, said motor being connected to the source of'current for thewindings on said primary core. l

5. A transformer comprising a main field -having cores and coils forminga stator and locked rotor, and an adjustable commutating field having acore and coils, said fields being iaxial alinement and being displacedapproximately 90 degrees in phase, a rotat ing commutator groupconnected to the coils of the locked rotor, means for adjusting saidcommutating field angularly relative to the main field, and means foractuating said rotating commutator group.

6. A transformercomprising a main field having cores and coils forming astator and locked rotor, and an adjustable commutating field having aOre and 0011s, Said fields bemg in axial alinement' and being displacedapproximatelyl() degrees in phase, a rotating commutator group connectedto the-coils of the locked rotor, means for adjusting said 'eommutatingfield angularly relative to the^ Amain field anda synchronous vmotor oraetuating saidl rotating commutator group,

said motorhaving terminals connected `in parallel with ythe primarycoils of said stator.4 Y

7. A transformer comprising a main field. having integrated primary andsecondary cores, and 'apluralityof coils on .said cores,`

y my hand.

a commutatingfield having a core and a plurality of ,ooilsf'thereom saidfields being and seoondary'eores of said main field, and eachvcorresponding'. group of the primary and stator coils :being similarlyconnected Y' to a source of power, a eommutator group Connected to thecoils of said .secondary core,

and collectors for' said eommutator group.

In testimony-whereof have hereunto set ARTHUR F; N'EsBrrj

